Six protocols are currently active and conducted out of the Consultation- Liaison Service-based behavioral medicine research program. These protocols examine the phenomenology and biological correlates of illness or treatment-induced mood, behavioral, and cognitive changes. The protocols address such areas as: a) the effects of previous psychiatric history on the psychiatric morbidity associated with certain diseases and their treatment; b) the psychiatric phenomenology of certain diseases and their treatment; c) the treatment response characteristics of psychiatric disorders associated with medical diseases or their treatment; d) biochemical factors that may serve as predictive diagnostic markers for illness or for treatment-associated mood/behavioral or cognitive syndromes; e) the effects of mood state alterations on immunologic function. Significant findings to date include demonstration of the following: 1) significant reduction in thyroid and reproductive axis activity during anabolic steroid administration; 2) significant increase in IL-2 and discoordination of IL-1 and IL-2 secretion by anabolic steroids; 3) evidence of significant cognitive impairment and negative affective symptoms in association with blunted endocrine response to anabolic steroids, with significant positive affective symptoms associated with more robust hormonal responses to anabolic steroids; 4) preliminary evidence of the antidepressant efficacy of thyroid hormone (T4) in patients with central hypothyroidism.